Evidence map›Paper›PMID 25748442›Full record

Trial reportClinical science (London, England : 1979)2015

Folic acid supplementation improves microvascular function in older adults through nitric oxide-dependent mechanisms.

Anna E Stanhewicz, Lacy M Alexander, W Larry Kenney

Open access · greenAbstract readComparative StudyRandomized Controlled Trial
PubMed Full text at PMC Publisher
In one paragraph

Trial report in Clinical science (London, England : 1979), 2015. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 32 papers, 1 of them a synthesis that pooled it.

0numbers the graph read from it
0cells of the map it votes in
32citing papers in PubMed, 1 pooled it
4.9field-weighted citation impact, top 5% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

32 citing papers in PubMed, 1 synthesis or guideline pooled it, 54 citations in OpenAlex.

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  19. The vitamin D-folate hypothesis in human vascular health.American journal of physiology. Regulatory, integrative and comparative physiology · 2019
    Review
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4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

3 authors at 1 institution in 1 country.

Anna E Stanhewicz*Department of Kinesiology, Noll Laboratory, Pennsylvania State University, University Park, PA, U.S.A.
Lacy M Alexander*Department of Kinesiology, Noll Laboratory, Pennsylvania State University, University Park, PA, U.S.A.
W Larry Kenney*Department of Kinesiology, Noll Laboratory, Pennsylvania State University, University Park, PA, U.S.A.
Pennsylvania State University · US

Funding

Age and Control of Human Skin FlowR01AG007004 · NIA · PENNSYLVANIA STATE UNIVERSITY-UNIV PARK · PI KENNEY, W. LARRY · 1994 to 2013
$4.9M
NIA NIH HHS R01 AG007004NIA NIH HHS R01 AG-07004-23
6 · The paper itself

Abstract

Older adults have reduced vascular endothelial function, evidenced by attenuated nitric oxide (NO)-dependent cutaneous vasodilatation. Folic acid and its metabolite, 5-methyltetrahydrofolate (5-MTHF), are reported to improve vessel function. We hypothesized that (i) local 5-MTHF administration and (ii) chronic folic acid supplementation would improve cutaneous microvascular function in ageing through NO-dependent mechanisms. There were two separate studies in which there were 11 young (Y: 22 ± 1 years) and 11 older (O: 71 ± 3 years) participants. In both studies, two intradermal microdialysis fibres were placed in the forearm skin for local delivery of lactated Ringer's solution with or without 5 mM 5-MTHF. Red cell flux was measured by laser-Doppler flowmetry. Cutaneous vascular conductance [CVC=red cell flux/mean arterial pressure] was normalized as percentage maximum CVC (%CVCmax) (28 mM sodium nitroprusside, local temperature 43°C). In study 1 after CVC plateaued during local heating, 20 mM NG-nitro-L-arginine methyl ester (L-NAME) was perfused at each site to quantify NO-dependent vasodilatation. The local heating plateau (%CVCmax: O = 82 ± 3 vs Y = 96 ± 1, P = 0.002) and NO-dependent vasodilatation (%CVCmax: O = 26 ± 6% vs Y = 49 ± 5, P = 0.03) were attenuated in older participants. 5-MTHF augmented the overall (%CVCmax = 91 ± 2, P = 0.03) and NO-dependent (%CVCmax = 43 ± 9%, P = 0.04) vasodilatation in older but not young participants. In study 2 the participants ingested folic acid (5 mg/day) or placebo for 6 weeks in a randomized, double-blind, crossover design. A rise in oral temperature of 1°C was induced using a water-perfused suit, body temperature was held and 20 mM L-NAME was perfused at each site. Older participants had attenuated reflex (%CVCmax: O = 31 ± 8 vs Y = 44 ± 5, P = 0.001) and NO-dependent (%CVCmax: O = 9 ± 2 vs Y = 21 ± 2, P = 0.003) vasodilatation. Folic acid increased CVC (%CVCmax = 47 ± 5%, P = 0.001) and NO-dependent vasodilatation (20 ± 3%, P = 0.003) in the older but not the young participants. Both local perfusion of 5-MTHF and supplementation with folic acid increase vasodilatation in ageing individuals through NO-dependent mechanisms.

Indexed as

Dietary SupplementsAdministration, CutaneousAdministration, OralAgedAge FactorsBlood Flow VelocityBody TemperatureCross-Over StudiesDouble-Blind MethodEnzyme InhibitorsFemaleFolic AcidHumansHypothermia, InducedMaleMicrocirculationEnzyme InhibitorsFolic AcidNitric OxideNitric Oxide Synthase Type IIINOS3 protein, humanVasodilator Agents

Identifiers

PMID25748442
PMCPMC8080301
OpenAlexW2028198245

What OpenQuestion holds

Textmetadata
LicenceTDM
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.